KR20010022254A - Methods and devices for controlling hydrocarbon oxidations to respective acids by adjusting the solvent to hydrocarbon ratio - Google Patents

Abstract

This invention relates to a method and apparatus for producing an acid such as adipic acid by oxidizing a hydrocarbon such as cyclohexane or the like with a gas containing an oxidizing substance which is preferably oxygen. The hydrocarbon preferably reacts with the gaseous oxidizing material in the steady state to produce an acid in the liquid mixture which preferably contains a solvent, a catalyst, water and an initiator. The ratio of solvent to hydrocarbon can be controlled by maintaining a reaction factor selected from the group consisting of reaction rate, reactivity, selectivity and yield within the appropriate range, or by moving the reaction factor toward the appropriate range.

Description

Methods and devices for controlling hydrocarbon oxidations to respective acids by adjusting the solvent to hydrocarbon ratio}

There are a myriad of references (patent literature and scholarly publications) concerning the production of acids, including those that oxidize hydrocarbons to produce adipic acid. Adipic acid is used to make nylon 66 fibers and composites such as resins, polyesters, polyurethanes, and the like.

The process for producing adipic acid varies. One conventional process involves the first step of oxidizing cyclohexane with oxygen to obtain a mixture of cyclohexanone and cyclohexanol (KA mixture) and then oxidizing the KA mixture with nitric acid to obtain adipic acid. Has a step. Other processes include the "Hydroperoxide Process", the "Boric Acid Process", and the "Direct Synthesis Process". The direct synthesis process includes solvents, catalysts, and accelerators. direct oxidation of cyclohexane to adipic acid using oxygen in the presence of promoters.

Direct synthesis processes have been noted for a long time. However, it has now been found that there is little commercial availability. One of the reasons is that although the process may seem very simple at first glance, it is actually very complex. Due to this complexity, people find that the views, comments and results they see in each literature are extremely conflicting.

It is well known that a reaction according to the direct synthesis takes place, and then, at room temperature, a mixture of a solid state material consisting mainly of adipic acid and a two liquid state material coexists. Two such liquid states are referred to as "Polar Phase" and Non-Polar Phase. However, except for the separation of adipic acid from the superfine material and the return of the two liquid materials to the reactor, whether or not with additional treatment, or some or all of them, are to be reused. Little attention has been given to the importance of the liquid state of dogs.

It cannot be overlooked that most of the work on direct oxidation has been done literally in batch mode, ie universally.

For example, there are numerous citations about oxidizing organic compounds to prepare intermediates such as acids such as adipic acid or cyclohexanone, cyclohexanol, cyclohexylhydroperoxide.

Among such references, reference is made to the following which are considered to be representative of representative oxidation processes for preparing diacids and intermediates.

U.S. Patent 5,463,119 (Kollar), U.S. Patent 5,374,767 (Drinkard et al.), U.S. Patent 5,321,157 (Kollar), U.S. Patent 3.987.100 (Barnette et al.), U.S. Patent 3,957,876 (Rapoport et al.), U.S. Patent 3,932,513 (Russell), U.S. Patent 3,530, 185 (Pugi), U.S. Patent 3,515,751 (Oberster et al.), U.S. Patent 3.361,806 (Lidov et al.), U.S. Patent 3,234, 271 to Barker et al., U.S. Pat. Patent 3,231,608 (Kollar). U.S. Patent 3,161,603 (Leyshon et al.), U.S. Patent 2,565,087 to Porter et al., U.S. Pat. Patent 2,557,282 to Hamblet et al., U.S. Patent 2,439,513 (Hamblet et al.), U.S. Patent 2,223,494 to Loder et al., U.S. Pat. Patent 2,223,493 (Loder et al.), German Patent DE 44 26 132 A1 (Kysela et al.), And PCT International Publication WO 96/03365 (Constantini et al.).

Any of the documents known to the inventors, including the above documents, either alone or in combination, are subject to oxidation reactions to obtain intermediates under the conditions of complex and critical control and requirements as described and claimed below. It does not specify, suggest or imply about it.

The present invention relates to a method and apparatus for directly treating a hydrocarbon such as cyclohexane and oxidizing it with an acid such as adipic acid.

The invention will be better understood by reading the following detailed description when viewing the accompanying drawings.

In the drawings, FIG. 1 is a block diagram schematically showing a preferred embodiment of this invention.

As described above, the present invention relates to a method and apparatus for directly treating a hydrocarbon such as cyclohexane and oxidizing it with an acid such as adipic acid. In particular, the invention produces an acid in a liquid mixture containing catalyst, solvent, water and optionally initiator with the catalyst, water and initiator at appropriate levels and the ratio of solvent to initial hydrocarbon determined. To control the oxidation of hydrocarbons in the reaction zone,

(a) contacting the liquid mixture with the gaseous oxidizing material in the reaction zone at a first temperature that is high enough to proceed oxidation;

and (b) controlling the ratio of hydrocarbon to solvent to be maintained within a range where the reaction rate or reactivity is at a maximum at an appropriate level for the catalyst, water and initiator.

The reaction rate is defined as the molecular weight of the oxide of the hydrocarbon per unit time.

Reactivity is defined as the reaction rate divided by the total of the mixture involved in the reaction, ie the reactivity per unit volume of the mixture involved in the reaction.

The term "proportion of solvent to hydrocarbon" in a continuous process is defined as the weight ratio of solvent to hydrocarbon at the outlet of the reaction zone described below. This is almost the same ratio of solvent to hydrocarbon in the steady state reaction chamber.

The term "steady state" means that the reaction is in equilibrium, but such equilibrium may be adjusted periodically or continuously to achieve the desired result.

The term "level" of a component (reactant, product, inert or other substance) means "relative level" and percentage level. The method and apparatus according to this invention can use any level thereof. In some cases it may be easier to use one of them than the other. The relative level of a component refers to the amount of the mass or volume unit of the component present in proportion to the unit of mass or volume of the residual component that is present or of the residual component under consideration. On the other hand, "percentage level" is a level expressed as a percentage of the total amount of the total or desired number of specific components. The percentage can be expressed in either weight ratio or volume ratio.

In one embodiment of the present invention, controlling the ratio of solvent to hydrocarbon initially includes increasing the ratio of solvent to hydrocarbon by a predetermined increment, wherein

(a) As the reaction rate or reactivity increases, the ratio of solvent to hydrocarbon continues to increase until it is recognized that there is no further increase in reaction rate or reactivity;

(b) If the reaction rate or reactivity is decreased, the ratio of solvent to hydrocarbon continues to decrease until it is recognized that there is no longer any increase in reaction rate or reactivity.

In another embodiment of the invention, controlling the ratio of solvent to hydrocarbon initially includes reducing the ratio of solvent to hydrocarbon by a predetermined increment, wherein

(a) As the reaction rate or reactivity increases, the ratio of solvent to hydrocarbon continues to decrease until it is recognized that there is no further increase in reaction rate or reactivity;

(b) If the rate or reactivity decreases, the ratio of solvent to hydrocarbon continues to increase until it is recognized that there is no longer any increase in rate or reactivity.

Even if the ratio of the solvent to the hydrocarbon is increased or decreased by a predetermined increment, and there is no change in the reaction rate or the reactivity, the ratio of the solvent to the hydrocarbon is preferably maintained at an initial value.

In addition, the invention produces an acid in a liquid mixture containing the catalyst, solvent, water and optionally initiator with the catalyst, water and initiator at an appropriate level and the ratio of solvent to initial hydrocarbon determined. In the method for controlling the oxidation of a hydrocarbon for the reaction zone,

(a) contacting the liquid mixture with the gaseous oxidizing material in the reaction zone at a first temperature that is high enough to proceed oxidation;

(b) in a manner appropriate to the level of catalyst, water and initiator, in which the reaction rate or reactivity is maintained within an appropriate range, or where the rate or reactivity of the solvent relative to the initial hydrocarbon is outside the appropriate range; And a step of controlling the ratio of hydrocarbon to solvent in a manner directed toward.

Controlling the ratio of solvent to hydrocarbon initially includes increasing the ratio of solvent to hydrocarbon by a predetermined increment, wherein

(a) When the rate or reactivity is shifted toward an appropriate range, the ratio of solvent to hydrocarbon is reduced to a rate where the rate or reactivity is within an appropriate range, or a rate at which the rate or reactivity no longer shifts to an appropriate range. Keep increasing,

(b) When the reaction rate or reactivity is far from the appropriate range, the solvent ratio to the hydrocarbon is reduced, and when the reaction rate or reactivity moves toward the appropriate range, the ratio of solvent to the hydrocarbon is adjusted to the reaction rate or reactivity range. It continues to decrease until the rate falls within or the rate at which the reaction rate or reactivity no longer moves toward the appropriate range.

Optionally, controlling the ratio of solvent to hydrocarbon may comprise initially reducing the ratio of solvent to hydrocarbon by a predetermined increment, wherein

(a) When the rate or reactivity is shifted toward an appropriate range, the ratio of solvent to hydrocarbon is reduced to a rate where the rate or reactivity is within an appropriate range, or a rate at which the rate or reactivity no longer shifts to an appropriate range. Keep reducing,

(b) If the reaction rate or reactivity is far from the appropriate range, increase the ratio of solvent to hydrocarbon, and if the reaction rate or reactivity moves toward the appropriate range, the ratio of solvent to hydrocarbon is within the range of appropriate reaction rate or reactivity. It continues to increase until the rate falls within, or the rate at which the reaction rate or reactivity no longer moves toward the appropriate range.

If the reaction rate or reactivity is within the appropriate range, the ratio of the solvent to the hydrocarbon is preferably maintained at the initial value.

The liquid mixture may be at least partially atomized to further increase the reaction rate or reactivity.

In one embodiment of this invention, the hydrocarbon comprises a compound selected from the group consisting of cyclohexane, cyclohexanone, cyclohexanol, cyclohexylhydroperoxide, o-xylene, m-xylene and p-xylene, and is an oxidizing substance Silver contains oxygen and most of the acids include compounds selected from the group consisting of adipic acid, phthalic acid, isophthalic acid) and terephthalic acid.

This method involves the production of polyesters, polyamides, or polymers of polyimide or polyamideimide to produce acids of polyols, polyamines and It may further comprise the step of reacting with polyamide. The method may include spinning the polymer into fibers.

The methods of the present invention may, in addition to or in addition to controlling the reaction rate or reactivity, in a substantially identical manner direct the oxidation of hydrocarbons to a good selectivity range or value or yield range or yield value, or It is also possible to utilize controlling the ratio of solvent to hydrocarbon in such a way as to keep the oxidation of the hydrocarbon within a good selectivity range.

According to this invention, selectivity such as, for example, acid selectivity, is defined as mole percent of the required amount of acid production relative to the total amount of acid. For example, in the case of adipic acid production, the number of moles of adipic acid produced in the reaction is divided by the number of moles of all produced acids (typically, adipic acid, glutamic acid, and succinic acid) and multiplied by 100. Acid selectivity is calculated.

The yield is defined as the number of moles of acid required to be actually produced divided by the number of moles of acid required to be produced theoretically and multiplied by 100.

The reaction rate, reactivity, selectivity and yield can be named as reaction factors that can be affected by the ratio of hydrocarbon to solvent.

The present invention relates to a compound selected from the group consisting of a hydrocarbon comprising cyclohexane, a catalyst comprising a cobalt compound, a solvent comprising acetic acid, and an initiator consisting of cyclohexanone, cyclohexylhydroperoxide, acetalaldehyde and mixtures thereof. It is particularly suitable when the gaseous oxidizing substance contains oxygen.

It is preferred that the liquid mixture reacting at the process temperature has substantially only one liquid state, with or without a solid state or liquid state. The presence of a second liquid state significantly lowers the reaction rate or reactivity.

The invention also relates to a reactor device for properly oxidizing hydrocarbons with individual oxidizing substances to produce acids in the presence of solvents, catalysts and optionally initiators.

Reaction chamber,

Supply means connected to the reaction chamber for supplying a gaseous oxidizing substance, a solvent, a hydrocarbon, a catalyst and optionally an initiator to the reaction chamber,

A control means connected to the supply means for controlling the rate of supply of hydrocarbons and solvents into the reaction chamber, i. It is characterized by.

The reaction apparatus may additionally include reaction rate or reactivity determining means connected to the reaction chamber to determine the reaction rate or reactivity in the reaction chamber.

The reactor may comprise an atomization reactor, a stirred tank reactor, a recycle reactor or a combination thereof or other reactors.

As described above, the present invention relates to a method and apparatus for directly treating a hydrocarbon such as cyclohexane and the like and oxidizing it with an acid such as adipic acid.

The reaction rates defined above, in particular the reactivity, are a very important factor because they make it possible to realize inexpensively any special process or equipment. Even in extreme cases where the conversion is 100% and the yield is 100%, if the reactivity is unacceptably low, the process is of course uneconomical.

According to this invention, the reaction rate or reactivity of the hydrocarbons to produce an acid can be maximized by controlling the ratio of solvent to hydrocarbon.

However, although maximizing the reaction rate or reactivity is highly preferred, if the conversion, selectivity, yield, etc. are balanced and exceed all the advantages obtained by maximizing the reaction rate or reactivity, the rate or reactivity is lower than the maximum value. It may be desirable to take. In such cases, the ratio of solvent to hydrocarbon is maintained at a level that controls the reaction rate or reactivity to be maintained within an appropriate range or to be lower than the maximum reaction rate or reactivity.

According to this invention, the ratio of solvent to hydrocarbon may be controlled such that the selectivity or yield is maximized or directed towards an appropriate range or maintained within an appropriate range. The examples below refer primarily to reaction rates or reactivity, but apply equally well to selectivity and yield.

This invention can be illustrated with reference to FIG. 1, a reaction system or apparatus 10 is shown that includes a reaction chamber 12 containing a reaction zone 14. The reaction system 10 is only partially shown to expose the components necessary to clarify this invention. Minor manipulations, products or by-products or regeneration and the like are not shown for the sake of clarity.

The reaction chamber 12 may be a stirred tank reactor, an atomization reactor, a recycle reactor or other reactors known in the art.

A plurality of supply lines that are at least part of the supply means 15 are connected to the reaction chamber 12, such as the general supply line 16, the solvent supply line 18, the hydrocarbon supply line 20, and the supply line 22 of the gaseous oxidizing substance. Is shown. These supply lines are shown to better illustrate this invention. However, these supply lines may include combined or recycled lines, or may include multiple or single lines and the like. The supply means 15 may comprise a heat exchanger, a premixing vessel, a flow rate, a thermocouple, etc., which are connected to one or more inlets 24 of the controller 26 (not shown for the sake of clarity). And the controller 26 is connected to the supply means 15 via one or more outlets 28 and the operation is controlled in a manner known in the art.

The valves 16a, 18a, 20a, 22a are connected to respective lines 16, 18, 20, 22 to convey the flow rate of each substance which is transferred to the reaction zone 14 of the reaction chamber 12 through these lines. To control. These valves are controlled by the discharge lines 16 ", 18", 20 ", 22" of the controller 26, respectively.

Flow rater 30 is connected to line 22 and monitors the flow of gaseous oxidizing material that is passed through line 22 into reaction zone 14 of reaction chamber 12. Flow rate information is provided to the controller 26 via an input line 30 ′ connected to the inlet 24 of the controller 26. Flow rates and other devices that provide information to controller 26 from lines 16, 18, and 20 are not shown for the sake of brevity. Means for controlling the temperature and pressure monitoring and the temperature and pressure of the reaction zone 14 of the reaction chamber 12 are also not shown for clarity, but they are well known in the art.

A discharge line 32 of the separator gas is connected to the reaction chamber 12 to remove the separator gas. Flux condensers, decanters, distillation columns or other devices known in the art that are useful for recycling thermally equilibrium materials are not shown for the sake of clarity.

The oxygen analyzer 34 is connected to the separator gas outlet 32 through the first sampling line 36 to analyze the content of oxygen in the separator gas. The oxygen content information is supplied to the controller 26 via an input line 34 'connected to the inlet 24 of the controller 26.

The reacting material in the reaction zone 14 of the reaction chamber 12 is removed via the discharge line 38 for further processing, separation and recycling of the oxidation product.

The analyzer 40 is connected to the discharge line 38 through the second sampling line 42 to analyze the components of the fluid passing through the discharge line 38, in particular hydrocarbons such as cyclohexane, which is related to the present invention. It may be. Of course, analyzer 40 may also analyze components of other fluids, including, but not necessarily, oxidation products such as solvents, water, adipic acid, and by-products such as succinic acid and glutamic acid. The analyzer 40 preferably includes an analytical instrument such as, for example, HPLC, GC, GC / MS, GC / FID, and the like. The analysis information is then provided to the controller 26 via an inlet line 40 ′ connected to the inlet 24 of the controller 26.

In operation of this embodiment, preferably hydrocarbons such as cyclohexane and the like are supplied via the line 20 to the reaction zone 14 of the reaction chamber 12 under steady state, and the solvent is supplied through the line 19. , Oxygen is supplied via line 22. The catalyst and optional water and optional initiator are supplied via line 16. As described above, lines 16, 18, and 20 are separated lines to better illustrate the present invention, even though there may be several materials present in these lines, such as solvents, hydrocarbons, catalysts, water, initiators, and minor impurities. Is shown. The controller calculates the composition of each fluid passing through the lines 16, 18, 20 at least partially depending on the information from the mass balance data, or an additional analyzer (not shown) included in the supply means 15 or elsewhere. Component measurements can be obtained from For simplicity it is assumed that all solvents are supplied via line 18 and all hydrocarbons are supplied via line 20.

Reaction rates and reactivity can be determined by the controller 26 in a number of ways. The information obtained from the flow rate device 30 provides the flow rate of the incoming oxidizing material, such as oxygen, and the information provided by the oxygen analyzer 34 relates to the flow rate of the outgoing oxidizing material. The flow rate difference between the incoming and outgoing oxidant is the actual value of the reaction rate. Reactivity can be calculated by considering the volume of non-gaseous material in the reaction chamber 12.

A more accurate method of determining the reaction rate is, for example, the flow rate of hydrocarbons and analyzers (for the sake of simplicity assuming that the total amount of hydrocarbons enters the reaction chamber 12 via line 20). It is determined from the difference in the flow rate of the hydrocarbon exiting the reaction chamber 12 through the line 38 as measured by 40). In this case, the reactivity can also be determined in consideration of the volume of the non-gaseous material in the reaction chamber 12.

Other methods of determining reaction rate or reactivity are described in detail in WO 98/07677 of the inventor of this invention, which is incorporated herein by reference.

As described above, the term "solvent to hydrocarbon ratio" in a continuous process is defined as the weight ratio of solvent to hydrocarbon at the exit of the reaction zone, ie the discharge line. This is substantially the same or at least very close to the ratio of solvent to hydrocarbon in reaction zone 14 of reaction chamber 12. Such discharge line is line 38. The analyzer 40 collects the sample fluid for the solvent and the hydrocarbon through the sampling line 42 in the line 38, from which the ratio of the solvent to the hydrocarbon is obtained. In the case of a comprehensive process, the ratio of solvent to hydrocarbon varies continuously, which cannot be easily controlled.

Then, in the process of this embodiment, the flow rate of the solvent flowing through the line 18 (assuming only the solvent entering the reaction zone 14 for the sake of simplicity passes through the line 18) is increased by a predetermined increment. , The flow rate of hydrocarbons in line 20 is decreased by increments, so that the total mass of solvent and hydrocarbons entering the reaction zone 14 is kept constant. It also changes the ratio of solvent to hydrocarbon entering the reaction zone 14 by a predetermined increment.

If the reaction rate or reactivity is increased, the ratio of solvent to hydrocarbon is further increased until the increase in reaction rate or reactivity is no longer recognized, and it is preferable to increase by a constant increment. If the reaction rate or reactivity is decreased by increasing the ratio of solvent to hydrocarbon, the ratio of solvent to hydrocarbon is lower than the ratio of solvent to initial hydrocarbon. If the reaction rate or reactivity is increased by this measure, the ratio of solvent to hydrocarbon is lowered until the increase in reaction rate or reactivity is no longer recognized.

Optionally (assuming only solvent entering the reaction zone 14 for the sake of brevity passes through line 18), the ratio of solvent to hydrocarbon is reduced by a predetermined increment and the hydrocarbon flow rate is increased by an increment. By doing so, the process may be initiated while keeping the total mass of solvent and hydrocarbon flowing into the reaction zone 14 constant. do. It also changes the ratio of solvent to hydrocarbon entering the reaction zone 14 by a predetermined increment.

If the reaction rate or reactivity is increased, the ratio of solvent to hydrocarbon is further reduced until the increase in reaction rate or reactivity is no longer recognized, preferably by a certain increment. If the reaction rate or reactivity is decreased by reducing the ratio of solvent to hydrocarbon, the ratio of solvent to hydrocarbon is increased to greater than that of the initial hydrocarbon. If the reaction rate or reactivity is increased by this measure, the ratio of solvent to hydrocarbon is further increased until the increase in reaction rate or reactivity is no longer recognized.

If increasing or decreasing the ratio of solvent to hydrocarbon by a predetermined increment does not change the reaction rate or reactivity, the ratio of solvent to hydrocarbon remains substantially at its initial value.

In many cases, it is desirable to keep within a defined range instead of maximizing the reaction rate or reactivity. In such a case, the process is similar to that described below.

The flow rate of the solvent may initially be increased by a predetermined increment such that the ratio of solvent to hydrocarbon is increased by a predetermined increment from that initial value. When the reaction rate or reactivity moves toward the appropriate reaction rate or reactivity range, the ratio of solvent to hydrocarbon is further increased by a predetermined increment until the reaction rate or reactivity falls within the above range.

If the reaction rate or reactivity is far from the appropriate reaction rate or range of reactivity, then the ratio of solvent to hydrocarbon is lowered, and if the reaction rate or reactivity moves toward the appropriate rate or range of reactivity, the ratio of solvent to hydrocarbon is The reaction rate or reactivity is further reduced until it falls within the appropriate range.

Optionally, the ratio of solvent to hydrocarbon may be reduced by a defined increment. When the reaction rate or reactivity moves toward the appropriate reaction rate or reactivity range, the ratio of solvent to hydrocarbon is further reduced until the reaction rate or reactivity falls within the appropriate range. If the reaction rate or reactivity is far from the proper reaction rate or reactivity range, the ratio of solvent to hydrocarbon is increased. When the reaction rate or reactivity moves toward the appropriate reaction rate or range of reactivity, the ratio of solvent to hydrocarbon is further increased until the reaction rate or reactivity falls within the appropriate range.

If the reaction rate or reactivity is within the appropriate reaction rate or reactivity range, the ratio of solvent to hydrocarbon is substantially maintained at its initial value.

The increment that changes the flow rate of the incoming solvent (along with the change in incoming hydrocarbon) is preferably 15% or less, more preferably 10% or less, and more preferably in the range of 2-7%. Thus, for example, if the initial solvent flow rate is 60 unit speed and the hydrocarbon flow rate is 40 unit speed, the change by the predetermined increment of the solvent is preferably 9 units or less, more preferably 6 units or less. More preferably in the range of 1.2 to 4.2 units. The change in hydrocarbon flow rate should be such that the sum of solvent units and hydrocarbon units is substantially equal to the total of 100 flow rate units.

The frequency and response of the incremental change depends on the size of the reaction zone 14 of the reaction chamber 12, the flow rate and optionally other factors. However, they can be easily determined depending on the individual situation.

The apparatus and method of the present invention instead of controlling the reactivity or reaction rate, or in addition thereto, guide the oxidation of hydrocarbons towards a range of good selectivity or yield, using substantially the same method as described above. However, it is also possible to use controlling the ratio of the solvent to the hydrocarbon in such a manner as to keep the oxidation of the hydrocarbon within a range of good selectivity and yield.

In the process of controlling the ratio of solvent to hydrocarbon, the level of catalyst and optional initiator and water in the reaction zone 14 of the reaction chamber 12 is preferably kept substantially constant. If they change for any reason, a new control of the ratio of solvent to hydrocarbon would be appropriate. As described above, in the above examples only, for the sake of clarity of the present invention, only solvent and hydrocarbons flowing into the reaction zone 14 are introduced through the respective lines 18 and 20 and other components are added to the other lines 16. It is assumed that the oxidizing material in the gaseous state enters the reaction zone 14 through the other line 22 and enters the reaction zone 14 through the other line 22. However, the controller 26 may control several lines of fluid in one way to achieve the same end result.

The reaction rate, reactivity, selectivity and yield may be named as reaction factors influenced by the ratio of hydrocarbon to solvent.

According to this invention, any liquid, gas or separator may be recycled from one zone to another.

Dibasic acids produced according to this invention (eg adipic acid, phthalic acid, isophthalic acid). Terephthalic acid and the like and other suitable compounds are selected from the group consisting of polyols, polyamines and polyamides in a manner which produces polyesters, polyamides or polymers of (polyimide or polyamideimide) by conventional well known methods. It may also be reacted with a third reactant. Preferably, polyols, polyamines and polyamides are mainly diols, diamines and diamides to avoid excessive crosslinking. The polymer resulting from this reaction may be spun by conventional well known methods to form fibers.

Computerized controllers are preferred as controllers. A good computerized controller is preferably an artificial intelligence system (a well known expert system, neural network and fuzzy logic system). Of these three types of artificial intelligence systems, the neural network system, a type of learning system, collects information (eg, pressure, temperature, chemical or other analytical values) from various locations on the device, and outputs this information (e.g., It is programmed to use this information in the future to make decisions about what to do in each case, along with other data that can be stored and used according to pressure drop rates, reaction rates, reactivity, etc.). Expert systems are programmed based on experienced human experience. Fuzzy logic systems are based on intuitive laws added to the rule of thumb.

Although fine functions are preferably controlled by a computerized controller, according to the present invention, other types of controllers may be used, such as a manual controller or an operator controlling one or more functions.

Oxidation according to this invention is nondestructive oxidation in which the oxidation product is not carbon monoxide, carbon dioxide and mixtures thereof, for example adipic acid or the like. Of course, small amounts of such compounds may also be produced with oxidation products which may be one product or a mixture.

Examples are provided, but are not limited to providing C ₅ -C ₈ aliphatic dibasic acids from saturated cycloaliphatic hydrocarbons, such as, for example, providing adipic acid from cyclohexane. Examples of aromatic carboxylic acids include benzoic acid, phthalic acid, isophthalic acid and terephthalic acid.

With regard to adipic acid, general information may be found in a number of US patents and the like, particularly suitable for the method and apparatus of the present invention. These documents are U.S. Pat. , and 5,321,157.

The examples illustrating the process of this invention are provided for purposes of illustration only and are not intended to limit the scope of the invention in any way. In addition, the preferred embodiments described in detail above may be implemented individually or in any combination according to common sense or expertise, as with any other embodiments that fall within the limits of this invention. In addition, the individual zones of the embodiments may be carried out in accordance with this invention, either individually or in combination with other individual zones of the embodiments or with the whole embodiment.

All statements made above should be considered theoretical and are not intended to limit the scope of the claims.

All percentages and ratios are in terms of mass unless otherwise defined.

Claims (13)

Reaction zone for the oxidation of hydrocarbons to produce acid in a liquid mixture containing catalyst, solvent, water and optionally initiator, with the catalyst, water and initiator at an appropriate level and the ratio of solvent to initial hydrocarbon determined. In the control method, (a) contacting the liquid mixture with the gaseous oxidizing material in the reaction zone at a first temperature that is high enough to proceed oxidation; (b) maintaining the ratio of solvent to hydrocarbon at the above levels of catalyst, water and initiator and the initial ratio of hydrocarbon to solvent within a substantially suitable range of reaction factors selected from the group consisting of reaction rate, reactivity, selectivity and yield; And controlling the ratio of the solvent to the hydrocarbon in such a manner as to guide the reaction factor toward the range if the method or the reaction factor is outside the range. The method of claim 1, Wherein said controlling step of controlling the ratio of solvent to hydrocarbon comprises initially increasing the ratio of solvent to hydrocarbon by a predetermined increment, wherein (a) when the reactant moves towards the range, the ratio of solvent to hydrocarbon continues to increase to the rate at which the reactant falls within the range, or to the rate at which the reactant no longer moves towards the range; , (b) if the reaction factor is far from the range, the solvent to hydrocarbon ratio is reduced; if the reaction factor is shifted toward the range, the ratio of solvent to hydrocarbon is within the appropriate range. Or continuously reduce the reaction factor to a rate at which the reaction factor no longer moves toward the range. The method of claim 1, The controlling step of controlling the ratio of the solvent to the hydrocarbon may include initially reducing the ratio of the solvent to the hydrocarbon by a predetermined increment, wherein (a) as the reactant moves towards the range, the ratio of solvent to hydrocarbon continues to decrease to the rate at which the reactant falls within the range, or to the rate at which the reactant no longer moves towards the range; , (b) if the reaction factor is far from the range, increase the ratio of solvent to hydrocarbon, and if the reaction factor moves toward the range, then the ratio of solvent to hydrocarbon is within the range Or continuously increase to a rate at which the reaction factor no longer moves toward the range. The method of claim 1, When the reaction factor is in the above range, the hydrocarbon oxidation control method characterized in that the ratio of the solvent to the hydrocarbon is substantially maintained at its initial value. The method according to claim 1, 2, 3 or 4, The hydrocarbon comprises a compound selected from the group consisting of cyclohexane, cyclohexanone, cyclohexanol, cyclohexylhydroperoxide, o-xylene, m-xylene and p-xylene, The oxidizing substance comprises oxygen, Most of the acids are hydrocarbon oxidation control method characterized in that it comprises a compound selected from the group consisting of adipic acid, phthalic acid, isophthalic acid and terephthalic acid. The method according to claim 1, 2, 3, 4 or 5, The hydrocarbon comprises cyclohexane, the catalyst comprises a cobalt compound, the solvent comprises acetic acid, the initiator is a compound selected from the group consisting of cyclohexanone, cyclohexylhydroperoxide, acetaldehyde and mixtures thereof And, wherein the gaseous oxidizing material includes oxygen. The method according to claim 1, 2, 3, 4, 5 or 6, Wherein said hydrocarbon is cyclohexane and said acid is adipic acid. The method according to claim 1, 2, 3, 4, 5, 6 or 7, Wherein said liquid mixture is substantially free of a second liquid state at said first temperature. The method according to claim 1, 2, 3, 4, 5, 6, 7, or 8, Additionally reacting the acid with a reactant selected from the group consisting of polyols, polyamines and polyamides in a manner that produces a polymer of polyester, polyamide or polyimide or polyamideimide. Hydrocarbon oxidation control method. The method of claim 9, And spinning the polymer into fibers. Apparatus for properly oxidizing hydrocarbons with individual oxidizing substances to produce acids in the presence of solvents and catalysts and optionally initiators, Reaction chamber, Supply means connected to the reaction chamber for supplying a gaseous oxidizing substance, a solvent, a hydrocarbon, a catalyst and optionally an initiator to the reaction chamber, Control the feed rate, ie flow rate, of hydrocarbons and solvents into the reaction chamber in such a way that the ratio of solvents to hydrocarbons is appropriately maintained to maintain or direct the reaction rate, reactivity, selectivity and yield within the appropriate ranges. Hydrocarbon oxidation apparatus characterized in that it comprises a control means connected to the supply means for. The method of claim 11, And a reaction factor determination means connected to the reaction chamber. The method according to claim 11 or 12, wherein And a hydrocarbon oxidation device comprising a reactor selected from the group comprising an atomization reactor, a stirred tank reactor, and a recycle reactor.